Introduce Sky packaged apps.

sky/examples/BUILD.gn

Index: sky/examples/BUILD.gn
diff --git a/examples/tiny/BUILD.gn b/sky/examples/BUILD.gn
similarity index 61%
copy from examples/tiny/BUILD.gn
copy to sky/examples/BUILD.gn
index 0a2c73a502ad066b538dedc49ae1bc42de41bc46..c47a7154b6b6f437888f3d51780214a1966bd89d 100644
--- a/examples/tiny/BUILD.gn
+++ b/sky/examples/BUILD.gn
@@ -2,10 +2,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//mojo/public/mojo_application.gni")
+group("examples") {
+  testonly = true
 
-mojo_native_application("tiny") {
-  sources = [
-    "tiny.c",
+  deps = [
+    "//sky/examples/hello_world:sky_hello_world",
   ]
 }